scholarly journals Time required for the restoration of normal heavy exercise V̇o2 kinetics following prior heavy exercise

2006 ◽  
Vol 101 (5) ◽  
pp. 1320-1327 ◽  
Author(s):  
Mark Burnley ◽  
Jonathan H. Doust ◽  
Andrew M. Jones
Keyword(s):  
Blood Lactate ◽  
Priming Effect ◽  
Slow Component ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
V̇o2 Kinetics ◽  
Time Required ◽  
Male Subjects

Prior heavy exercise markedly alters the O2 uptake (V̇o2) response to subsequent heavy exercise. However, the time required for V̇o2 to return to its normal profile following prior heavy exercise is not known. Therefore, we examined the V̇o2 responses to repeated bouts of heavy exercise separated by five different recovery durations. On separate occasions, nine male subjects completed two 6-min bouts of heavy cycle exercise separated by 10, 20, 30, 45, or 60 min of passive recovery. The second-by-second V̇o2 responses were modeled using nonlinear regression. Prior heavy exercise had no effect on the primary V̇o2 time constant (from 25.9 ± 4.7 s to 23.9 ± 8.8 s after 10 min of recovery; P = 0.338), but it increased the primary V̇o2 amplitude (from 2.42 ± 0.39 to 2.53 ± 0.41 l/min after 10 min of recovery; P = 0.001) and reduced the V̇o2 slow component (from 0.44 ± 0.13 to 0.21 ± 0.12 l/min after 10 min of recovery; P < 0.001). The increased primary amplitude was also evident after 20–45 min, but not after 60 min, of recovery. The increase in the primary V̇o2 amplitude was accompanied by an increased baseline blood lactate concentration (to 5.1 ± 1.0 mM after 10 min of recovery; P < 0.001). Baseline blood lactate concentration was still elevated after 20–60 min of recovery. The priming effect of prior heavy exercise on the V̇o2 response persists for at least 45 min, although the mechanism underpinning the effect remains obscure.

scholarly journals Effect of pedal rate on primary and slow-component oxygen uptake responses during heavy-cycle exercise

2003 ◽  
Vol 94 (4) ◽  
pp. 1501-1507 ◽  
Author(s):  
Jamie S. M. Pringle ◽  
Jonathan H. Doust ◽  
Helen Carter ◽  
Keith Tolfrey ◽  
Andrew M. Jones
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Slow Component ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Motor Units ◽  
Primary Component ◽  
Heavy Exercise ◽  
Cycle Exercise ◽  
Pedal Rate

We hypothesized that a higher pedal rate (assumed to result in a greater proportional contribution of type II motor units) would be associated with an increased amplitude of the O2 uptake (V˙o 2) slow component during heavy-cycle exercise. Ten subjects (mean ± SD, age 26 ± 4 yr, body mass 71.5 ± 7.9 kg) completed a series of square-wave transitions to heavy exercise at pedal rates of 35, 75, and 115 rpm. The exercise power output was set at 50% of the difference between the pedal rate-specific ventilatory threshold and peakV˙o 2, and the baseline power output was adjusted to account for differences in the O2 cost of unloaded pedaling. The gain of the V˙o 2primary component was significantly higher at 35 rpm compared with 75 and 115 rpm (mean ± SE, 10.6 ± 0.3, 9.5 ± 0.2, and 8.9 ± 0.4 ml · min−1 · W−1, respectively; P < 0.05). The amplitude of theV˙o 2 slow component was significantly greater at 115 rpm (328 ± 29 ml/min) compared with 35 rpm (109 ± 30 ml/min) and 75 rpm (202 ± 38 ml/min) ( P < 0.05). There were no significant differences in the time constants or time delays associated with the primary and slow components across the pedal rates. The change in blood lactate concentration was significantly greater at 115 rpm (3.7 ± 0.2 mM) and 75 rpm (2.8 ± 0.3 mM) compared with 35 rpm (1.7 ± 0.4 mM) ( P < 0.05). These data indicate that pedal rate influences V˙o 2 kinetics during heavy exercise at the same relative intensity, presumably by altering motor unit recruitment patterns.

Early adaptations in blood substrates, metabolites, and hormones to prolonged exercise training in man

1991 ◽  
Vol 69 (8) ◽  
pp. 1222-1229 ◽  
Author(s):  
H. J. Green ◽  
S. Jones ◽  
M. Ball-Burnett ◽  
I. Fraser
Keyword(s):  
Uric Acid ◽  
Exercise Training ◽  
Blood Lactate ◽  
Prolonged Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Exercise Session ◽  
Average Intensity ◽  
Exercise Induced ◽  
Male Subjects

This study was designed to investigate the effect of short-term, submaximal training on changes in blood substrates, metabolites, and hormonal concentrations during prolonged exercise at the same power output. Cycle training was performed daily by eight male subjects ([Formula: see text], [Formula: see text]) for 10–12 days with each exercise session lasting for 2 h at an average intensity of 59% of [Formula: see text]. This training protocol resulted in reductions (p < 0.05) in blood lactate concentration (mM) at 15 min (2.96 ± 0.46 vs. 1.73 ± 0.23), 30 min (2.92 ± 0.46 vs. 1.70 ± 0.22), 60 min (2.96 ± 0.53 vs. 1.72 ± 0.29), and 90 min (2.58 ± 1.3 vs. 1.62 ± 0.23) of exercise. The reduction in blood lactate was also accompanied by lower (p < 0.05) concentrations of both ammonia and uric acid. Similarly, following training lower concentrations (p < 0.05) were observed for blood β-hydroxybutyrate (60 and 90 min) and serum free fatty acids (90 min). Blood glucose (15 and 30 min) and blood glycerol (30 and 60 min) were higher (p < 0.05) following training, whereas blood alanine and pyruvate were unaffected. For the hormones insulin, glucagon, epinephrine, and norepinephrine, only epinephrine and norepinephrine were altered with training. For both of the catecholamines, the exercise-induced increase was blunted (p < 0.05) at both 60 and 90 min. As indicated by the changes in blood lactate, ammonia, and uric acid, a depression in glycolysis and IMP formation is suggested as an early adaptive response to prolonged submaximal exercise training.Key words: exercise, training, blood metabolites, substrates, hormones.

Day-to-day variability in cardiorespiratory responses to hypoxic cycle exercise

2015 ◽  
Vol 40 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Meaghan J. MacNutt ◽  
Carli M. Peters ◽  
Catherine Chan ◽  
Jason Moore ◽  
Serena Shum ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Perceived Exertion ◽  
Minute Ventilation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Repeated Testing ◽  
Cycle Exercise ◽  
Cardiorespiratory Responses ◽  
Training Response ◽  
Hypoxic Exercise

Repeatedly performing exercise in hypoxia could elicit an independent training response and become an unintended co-intervention. The primary purposes of this study were to determine if hypoxic exercise responses changed across repeated testing and to assess the day-to-day variability of commonly used measures of cardiorespiratory and metabolic responses to hypoxic exercise. Healthy young males (aged 23 ± 2 years) with a maximal O2 consumption of 50.7 ± 4.7 mL·kg−1·min−1 performed 5 trials (H1 to H5) over a 2-week period in hypoxia (fraction of inspired oxygen = 0.13). Participants completed 3-min stages at 20%, 40%, 60%, and 10% of individual peak power. With increasing cycle exercise intensity there were increases in minute ventilation, O2 consumption, CO2 production, respiratory exchange ratio, heart rate (HR), blood lactate concentration, and ratings of perceived exertion for legs and respiratory system along with a reduction in oxyhaemoglobin saturation (%SpO2) (all p < 0.001). There were no systematic changes from H1 to H5 (p > 0.05). Most measures were highly repeatable across testing sessions with the coefficient of variation (CV) averaging ≤10% of the mean value in all variables except O2 consumption (17%), CO2 production (11%) and blood lactate concentration (17%). For HR and %SpO2 the CV was <5%. The exercise protocol did not elicit a training response when repeated 5 times during a 2-week period and the variability of exercise responses was low. We conclude that this protocol allows detection of small changes in cardiorespiratory responses to hypoxic exercise that might occur during exposure to hypoxia.

The V˙o 2 slow component for severe exercise depends on type of exercise and is not correlated with time to fatigue

1998 ◽  
Vol 85 (6) ◽  
pp. 2118-2124 ◽  
Author(s):  
Veronique L. Billat ◽  
Ruddy Richard ◽  
Valerie M. Binsse ◽  
Jean P. Koralsztein ◽  
Philippe Haouzi
Keyword(s):  
Blood Lactate ◽  
Slow Component ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Muscular Contraction ◽  
Work Rate ◽  
Severe Exercise ◽  
The Difference ◽  
Lactate Levels ◽  
Type Of Exercise

The purpose of this study was to examine the influence of the type of exercise (running vs. cycling) on the O2uptake (V˙o 2) slow component. Ten triathletes performed exhaustive exercise on a treadmill and on a cycloergometer at a work rate corresponding to 90% of maximalV˙o 2 (90% work rate maximalV˙o 2). The duration of the tests before exhaustion was superimposable for both type of exercises (10 min 37 s ± 4 min 11 s vs. 10 min 54 s ± 4 min 47 s for running and cycling, respectively). TheV˙o 2 slow component (difference between V˙o 2 at the last minute and minute 3 of exercise) was significantly lower during running compared with cycling (20.9 ± 2 vs. 268.8 ± 24 ml/min). Consequently, there was no relationship between the magnitude of theV˙o 2 slow component and the time to fatigue. Finally, because blood lactate levels at the end of the tests were similar for both running (7.2 ± 1.9 mmol/l) and cycling (7.3 ± 2.4 mmol/l), there was a clear dissociation between blood lactate and the V˙o 2slow component during running. These data demonstrate that 1) theV˙o 2 slow component depends on the type of exercise in a group of triathletes and 2) the time to fatigue is independent of the magnitude of theV˙o 2 slow component and blood lactate concentration. It is speculated that the difference in muscular contraction regimen between running and cycling could account for the difference in theV˙o 2 slow component.

The influence of execution speed on blood lactate concentration in strength training protocol in bench press exercise

2020 ◽  
Vol 19 (1) ◽  
pp. 32
Author(s):  
Gustavo Taques Marczynski ◽  
Luís Carlos Zattar Coelho ◽  
Leonardo Emmanuel De Medeiros Lima ◽  
Rodrigo Pereira Da Silva ◽  
Dilmar Pinto Guedes Jr ◽  
...  
Keyword(s):  
Strength Training ◽  
Blood Lactate ◽  
Bench Press ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
The Third ◽  
Fast Speed ◽  
Work Volume ◽  
Execution Speed ◽  
Training Protocol

The aim of this study was to analyze the influence of two velocities of execution relative to blood lactate concentration in strength training exercise until the momentary concentric failure. Fifteen men (29.1 ± 5.9 years), trained, participated in the experiment. The volunteers performed three bench press sessions, with an interval of 48 hours between them. At the first session, individuals determined loads through the 10-12 RMs test. In the following two sessions, three series with 90 seconds of interval were performed, in the second session slow execution speed (cadence 3030) and later in the third session fast speed (cadence 1010). For statistical analysis, the Student-T test was used for an independent sample study and considered the value of probability (p) ≤ 0.05 statistically significant. By comparing the number of repetitions and time under tension of the two runs, all series compared to the first presented significant reductions (p < 0.05). The total work volume was higher with the fast speed (p < 0.05). The study revealed that rapid velocities (cadence 1010) present a higher concentration of blood lactate when compared to slow runs (cadence 3030). The blood lactate concentration, in maximum repetitions, is affected by the speed of execution.Keywords: resistance training, cadence, blood lactate.

scholarly journals Effect of PEMF on Muscle Oxygenation during Cycling: A Single-Blind Controlled Pilot Study

2021 ◽  
Vol 11 (8) ◽  
pp. 3624
Author(s):  
Aurelio Trofè ◽  
Milena Raffi ◽  
David Muehsam ◽  
Andrea Meoni ◽  
Francesco Campa ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Slow Component ◽  
Local Level ◽  
Lactate Concentration ◽  
Oxygenation Index ◽  
State Level ◽  
Acute Effect ◽  
Primary Component ◽  
Muscle Oxygenation ◽  
Oxygen Kinetics

Pulsed electromagnetic fields (PEMFs) are used as non-invasive tools to enhance microcirculation and tissue oxygenation, with a modulatory influence on the microvasculature. This study aimed to measure the acute effect of PEMF on muscle oxygenation and its influence on pulmonary oxygen kinetics during exercise. Eighteen male cyclists performed, on different days, a constant-load exercise in both active (ON) and inactive (OFF) PEMF stimulations while deoxyhemoglobin and pulmonary oxygen kinetics, total oxygenation index, and blood lactate were collected. PEMF enhanced muscle oxygenation, with higher values of deoxyhemoglobin both at the primary component and at the steady-state level. Moreover, PEMF accelerated deoxyhemoglobin on-transition kinetic, with a shorter time delay, time constant, and mean response time than the OFF condition. Lactate concentration was higher during stimulation. No differences were found for total oxygenation index and pulmonary oxygen kinetics. Local application of a precise PEMF stimulation can increase the rate of the muscle O2 extraction and utilization. These changes were not accompanied by faster oxygen kinetics, reduced oxygen slow component, or reduced blood lactate level. It seems that oxygen consumption is more influenced by exercise involving large muscle mass like cycling, whereas PEMF might only act at the local level.

Effects of cocaine on incremental treadmill exercise in horses

1993 ◽  
Vol 75 (6) ◽  
pp. 2727-2733 ◽  
Author(s):  
K. H. McKeever ◽  
K. W. Hinchcliff ◽  
D. F. Gerken ◽  
R. A. Sams
Keyword(s):  
Right Ventricular ◽  
Blood Lactate ◽  
Venous Blood ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Ventricular Pressure ◽  
Mixed Venous Blood ◽  
Work Intensity ◽  
Venous Blood Lactate ◽  
Mixed Venous

Four mature horses were used to test the effects of two doses (50 and 200 mg) of intravenously administered cocaine on hemodynamics and selected indexes of performance [maximal heart rate (HRmax), treadmill velocity at HRmax, treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l, maximal mixed venous blood lactate concentration, maximal treadmill work intensity, and test duration] measured during an incremental treadmill test. Both doses of cocaine increased HRmax approximately 7% (P < 0.05). Mean arterial pressure was 30 mmHg greater (P < 0.05) during the 4- to 7-m/s steps of the exercise test in the 200-mg trial. Neither dose of cocaine had an effect on the responses to exertion of right atrial pressure, right ventricular pressure, or maximal change in right ventricular pressure over time. Maximal mixed venous blood lactate concentration increased 41% (P < 0.05) with the 50-mg dose and 75% (P < 0.05) with the 200-mg dose during exercise. Administration of cocaine resulted in decreases (P < 0.05) in the treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l from 6.9 +/- 0.5 and 6.8 +/- 0.9 m/s during the control trials to 4.4 +/- 0.1 m/s during the 200-mg cocaine trial. Cocaine did not alter maximal treadmill work intensity (P > 0.05); however, time to exhaustion increased by approximately 92 s (15%; P < 0.05) during the 200-mg trial.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Peripheral Modulators of the Central Fatigue Development and Their Relationship with Athletic Performance in Jumper Horses

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 743
Author(s):  
Francesca Arfuso ◽  
Claudia Giannetto ◽  
Elisabetta Giudice ◽  
Francesco Fazio ◽  
Michele Panzera ◽  
...  
Keyword(s):  
Blood Lactate ◽  
Athletic Performance ◽  
Lactate Concentration ◽  
Indirect Evidence ◽  
Blood Lactate Concentration ◽  
Central Fatigue ◽  
Serotoninergic System ◽  
Stressful Situation ◽  
Passive Behavior ◽  
Fatigue Development

The current study aimed to investigate whether peripheral modulators of serotoninergic function and neurohumoral factors’ changes in athletic horses during an official jumping competition, and to evaluate their relationship with the physical performance of competing horses. From 7 Italian Saddle mares (6–9 years; mean body weight 440 ± 15 kg), performing the same standardized warm-up and jumping course during an official class, heart rate (HR) was monitored throughout the competition. Rectal temperature (RT) measurement, blood lactate and glucose concentration, serum tryptophan, leucine, valine, the tryptophan/branched-chain amino-acids ratio (Try/BCAAs), dopamine, prolactin, and non-esterified fatty acids (NEFAs) were assessed before the exercise event (T0), at the end of the competition stage (5 min ± 10 s following the cessation of the exercise, TPOST5), and 30 min after the end of competition (TPOST30). Highest HR values were recorded during the course and at the outbound (p < 0.0001); blood lactate concentration and RT increased after exercise with respect to the rest condition (p < 0.0001). Lower leucine and valine levels (p < 0.01), and higher tryptophan, Try/BCAAs ratio, and NEFAs values were found at TPOST5 and TPOST30 with respect to T0 (p < 0.0001). A higher prolactin concentration was found at TPOST5 and TPOST30 compared to T0 (p < 0.0001), whereas dopamine showed decreased values after exercise compared to rest (p < 0.0001). Statistically significant correlations among the peripheral indices of serotoninergic function, neurohumoral factors, and athletic performance parameters were found throughout the monitoring period. The findings provide indirect evidence that the serotoninergic system may be involved in fatigue during jumper exercise under a stressful situation, such as competition, in which, in addition to physical effort, athletic horses exhibit more passive behavior.

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